Amorphous metal-aluminophosphate catalysts for aldol condensation of n-heptanal and benzaldehyde to jasminaldehyde

Hamza, A.; Nagaraju, N.

doi:10.1016/s1872-2067(14)60206-0

Cited by 23 publications

(15 citation statements)

References 20 publications

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“…The m-AlPO catalytic materials which are prepared in hot condition exhibits weak angle diffraction bands whereas in cold condition broad bands are shown. In addition, clear cut small particle size and high surface area samples are attained in hot condition compared to the samples prepared in cold [27,40]. Thus, amorphous and mesoporous nature of the catalytic materials have been clearly shown by weak angle diffraction peaks of PXRD patterns.…”

Section: Tsamentioning

confidence: 94%

“…In addition, the tetravalent metal acidic strength of ZrAlPO (m 4+ ) is lower due to reduction in acidic sites due to decreased formation of anionic vacancies. The substitution of Al 3+ by the tetravalent metal Zr (Zr 4+ ), which in turn leads to the formation of excess positive charge, causes the formation of weak acid sites (Lewis) rather than strong acid sites (Brønsted) [40]. (35.8) in m-AlPO solid samples [41,42].…”

Section: Tsamentioning

confidence: 99%

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Highly efficient conversion of glycerol and t-butanol to biofuel additives over AlPO solid acid catalyst under microwave irradiation technique: kinetic study

Prasad¹,

Shamshuddin²

2022

Comptes Rendus. Chimie

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Metal-aluminophosphate solid acids (m-AlPO) were prepared and characterized by various techniques such as powder-XRD, FT-IR, BET surface area, SEM, TEM, EDAX, NH 3 -TPD/n-butylamine back titration and ICP-OES techniques. These materials were used as catalysts in liquid phase etherification reaction of glycerol with alcohol. In order to obtain good yield of the reaction product, optimization reaction was carried out by varying time, temperature, catalyst weight and molar ratio of reactants. CuAlPO solid acid showed superior performance in a short period of time with 95% glycerol conversion and 68% selectivity to higher ethers (di and tri). The catalytic activity was investigated by three heating techniques (microwave, ultrasonic and conventional). The pre-adsorption experiment obeys the Langmuir-Hinshelwood type mechanism. Kinetic studies were also carried out to determine the activation energy (E a ) and temperature coefficient (T c ) of the catalyst. The catalyst was reused for several reaction cycles without much loss of catalytic activity.

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Section: Tsamentioning

confidence: 94%

Section: Tsamentioning

confidence: 99%

Highly efficient conversion of glycerol and t-butanol to biofuel additives over AlPO solid acid catalyst under microwave irradiation technique: kinetic study

Prasad¹,

Shamshuddin²

2022

Comptes Rendus. Chimie

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“…Owing to the lower price of synthetic materials, their higher stability in acidic, basic, and even oxidizing media, these compounds became more attractive to be used in the synthesis of perfumery chemicals [2]. Jasminaldehyde can be synthesized via the cross aldol condensation of heptanal (C 7 H 14 O) and benzaldehyde (C 7 H 6 O) (Scheme 1), and this process has been intensively studied by researchers to enhance the yield of jasminaldehyde [3][4][5][6][7][8][9][10]. In addition to jasminaldehyde, the self-condensation of heptanal resulted in the formation of 2-n-pentyl-2-n-nonenal (C 14 H 26 O) as the main by-product of this reaction.…”

Section: Introductionmentioning

confidence: 99%

“…Hamza and Nagaraju [7] investigated the synthesis of jasminaldehyde using the amorphous metal-aluminophosphate catalysts (MAlPs), where M is 2.5 mol.% Cu, Fe, Zr, Cr, Zn, or Ce. The aldol condensation reaction was performed in a three-necked round bottom flask with the benzaldehyde to heptanal ratio of 5.…”

Section: Introductionmentioning

confidence: 99%

Solvent-Free Synthesis of Jasminaldehyde in a Fixed-Bed Flow Reactor over Mg-Al Mixed Oxide

et al. 2020

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In spite of the rapid developments in synthesis methodologies in different fields, the traditional methods are still used for the synthesis of organic compounds, and regardless of the type of chemistry, these reactions are typically performed in standardized glassware. The high-throughput chemical synthesis of organic compounds such as fragrant molecules, with more economic benefits, is of interest to investigate and develop a process that is more economical and industrially favorable. In this research, the catalytic activity of Mg-Al catalyst derived from hydrotalcite-like precursors with the Mg/Al molar ratio of 3 was investigated for the solvent-free synthesis of jasminaldehyde via aldol condensation of benzaldehyde and heptanal. The reaction was carried out in a fixed-bed flow reactor, at 1 MPa, and at different temperatures. Both Brønsted and Lewis (O2− anions) base sites, and Lewis acid sites exist on the surface of the Mg-Al catalyst, which can improve the catalytic performance. Increasing the reaction temperature from 100 °C to 140 °C enhanced both heptanal conversion and selectivity to jasminaldehyde. After 78 h of reaction at 140 °C, the selectivity to jasminaldehyde reached 41% at the heptanal conversion 36%. Self-condensation of heptanal also resulted in the formation of 2-n-pentyl-2-n-nonenal. The presence of weak Lewis acid sites creates a positive charge on the carbonyl group of benzaldehyde, and makes it more prone to attack by the carbanion of heptanal. Heptanal, is an aliphatic aldehyde, with higher activity than benzaldehyde. Therefore, the possibility of activated heptanal reacting with other heptanal molecules is higher than its reaction with the positively charged benzaldehyde molecule, especially at a low molar ratio of benzaldehyde to heptanal.

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“…Metal phosphates are fascinating inorganic materials because of their unique ability in electro‐catalysis, photo‐catalysis, and heterogeneous catalysis . One of these, zirconium phosphate (ZrP) has been used in various heterogeneous catalytic reactions, such as alcohol dehydration, esterification, hydrogenation and substitution .…”

Section: Introductionmentioning

confidence: 99%

Amorphous Porous Chromium‐Zirconium Bimetallic Phosphate: Synthesis, Characterization and Application in Liquid Phase Oxidation of Hydrocarbons by Different Oxygen Sources

et al. 2020

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CrÀ Zr bimetallic phosphates catalysts were prepared by sol-gel method and used in the oxidation of cyclohexane, ethylbenzene and cyclohexene, respectively. The catalysts were characterized by a variety of analytical techniques. The results show that chromium ions enter the framework of mesoporous zirconium phosphate, CrÀ Zr phosphates catalysts with molar ratio of Cr: Zr = 2 (CrZr 2 P) or Cr: Zr = 1 (CrZrP) still retain the mesoporous structure and form composite metal phosphates. Two active centers-redox (Cr 6 + ) and acidic sites in these bimetallic phosphates play a synergistic catalytic role in the oxidation of CÀ H bond. Catalytic activity is closely related to the amount of acid or acid strength, the C=O product selectivity depends on the amount and high dispersion of Cr 6 + species. Acidic sites and redox sites are affected by different molar ratios of chromium/ zirconium. Among the CrÀ Zr phosphates catalysts, CrZr 2 P and CrZrP catalysts show excellent activity, just because the formation of mesoporous structure leads to the uniform dispersion of acidic and redox sites.[a] L.

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Amorphous metal-aluminophosphate catalysts for aldol condensation of n-heptanal and benzaldehyde to jasminaldehyde

Cited by 23 publications

References 20 publications

Highly efficient conversion of glycerol and t-butanol to biofuel additives over AlPO solid acid catalyst under microwave irradiation technique: kinetic study

Highly efficient conversion of glycerol and t-butanol to biofuel additives over AlPO solid acid catalyst under microwave irradiation technique: kinetic study

Solvent-Free Synthesis of Jasminaldehyde in a Fixed-Bed Flow Reactor over Mg-Al Mixed Oxide

Amorphous Porous Chromium‐Zirconium Bimetallic Phosphate: Synthesis, Characterization and Application in Liquid Phase Oxidation of Hydrocarbons by Different Oxygen Sources

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